Visible spark plug



A.T. CRiANE.

VISIBLE SPARK PLUG.

APPLICATION FILED MAR. 5. 1921.

1,425,749. I Patented Aug. 15, 1922.

I l7 /s ARTHUR T. CRANE, OF,WATERBURY, CONNEQTICUT, ASSIGNOR To THE CHASE COMPANIES INC., 035 WVATERBURY, CQNNECTIC'UT, A CORPORATIOLL vrsrnnn sPnnK PLUG.

To all whom it may concern.

' Be it known that I, ARTHUR T. Creme-a citizen of the United States, residing at \Vaterbury, in the county of New Haven and State of Connecticut, have invented a new and useful Improvement in Visible Spark Plugs; and I do hereby declare the following, when taken in connection with the accompanying drawings andthe characters of reference marked thereon, to be a full,

clear, andexact description of the same, and which said drawings constitute part ofthis.

cap partly in side elevation and partly in vertical section before the spinning inward of its beads.

Fig. 6 a detached sparking-disk.

Fig. 7 a detached edge view of the lens.

My invention relates to an improvement in that class of visible spark-plugs in which the terminal-screw is located directly above and in line with the electrode, so as to permit the socket-wrench employed for installing and removing the plug to be axially passed down over the plug and lifted off the same, the object of my present invention being to produce a single, compact and durable plug, composed of few parts, convenient in use and reliable in performance.

with these ends in view, my invention consists in a visible. spark-plug having certain details of constructions and combinations of parts as will be hereinafter described and pointed out in the claims.

In carrying out my invention as herein shown, I employ a sparking-disk 10, having its center struck downwardly to form a conperspective view I of the ical sparking-boss 11, and formed with three segmental observation-openings 12, grouped in a circle around the said boss, equally spaced apart and registering with three corresponding observation-openings 13 formed in the concavo-convex upper wall 141 of the lens-chamber15 of a sheet-metal Specification ofLetters Patent, pafl gnted-Aug Application medical-ch 5, 1921, SerialNo. 449,720.

.in correct position thereupon,

mounting-cap 1.6,thc said chamber receiving a plano convex lens 17, which fills the said chamber, and the flat lower face of which rests upon the upper face of the said disk, the edge of which rests upon an inwardlyprojecting annularbead 1Sspun in the metal of the cap 16 after the introduction of the said lens and disk into the said; lenschamber. f 4 I: Under the'construction described, the user of the plug is enabled to look downward through the observation-openings 913, through the lens 17, and through the observatio l-openings 12in the disk and observe the electrode 19 in the sparking chamber 20, which is located directly below the lens-chamber and furnished with a plurality of ventilating} openings 21, through which the ozone escapes to prevent the discoloration of the lens and which also permits the operation of the plug to be observed, the sparking-chamber 20 being illuminated by the passage of the spark from the. electrode 19 to the sparking-boss 11 of the sparking-disk 10. An inwardly-projecting annular spacingbead 22, spun into the metal of the cap 16, rests upon the upper edge of the core 23 and inounts the cap 16 7 so as to produce the sparking-chamber 20, which occupies the space between the sparking-disk 10 and the upper face of the core, to which the cap is secured by spinning its lower edge 1nto an annular groove 24 therein for the production of the retaining-flange 25. As sl1o wn, ,the mounting-cap 16 is spun to form at ts upper end, a concentric, hollow boss 26 rising from the concavo-convex wall 14 of the lens-chamber and in turn formed with a concentric, hollow terminal-screw 27 mounting the terminal-nut 28, but if preferred the screw may be made independent of and rigidly mounted in the mountingcap in the well-known manner. I v

I would have it understood that I do not limit myself to the exact structure herein shown and described, my present invention being directed to the use of a sparking-disk formed with observation-openings register- ,lng wlth correspondlng observatlon openings formed in a Iclaim: g 1. A visible spark-plug having its cap provided with a' lens-chamber and with 0bportion of the mounting-cap.

servation-openings leading thereinto, a lens- 2. A visible spark-plug having a sparkingchamber, an electrode projecting thereinto, a sparking-disk having a sparkingpoint located in line wlth the axis of the electrode, and provided with observationopenings located at one side of its center, and'a lens-chamber having corresponding observatioiropenings located at one side of its center and registering with the said ohservation-openings in the sparking-disk.

3. A visible spark-plug having a sparking-chamber, an electrode projecting thereinto and a sparking-disk located above the sparking-chamber and formed with a concentric downwardly projecting sparkingboss for co-action with the electrode, and with observation-openings through which the interior of the sparking-chamber may be observed.

4. In a visible spark'plug, the combination with a mounting-cap comprising a sparking-chamber, and a lens-chamber located in line with the said electrode, and

with observation-openings located at one side of its center in position to register with the observation-openings in the concavoconvex wall of the lens-chamber.

5. A visible spark-plug having a lenschamber, a sparlring-chainber an electrode projecting into the said sparking-chamber, a lens located in the lens-chamber, and a sparking-disk interposed between the said chambers and provided with a. sparkingpoint locatedin line with the axis of the electrode. i

In testimony whereof, I have signed this specification in the presence of two subscribing witnesses.

ARTHUR T. CRAN Witnesses:

JOHN S. NEAGLE, ALICE F. HEALY. 

